WC is included in both AES and S/PDIF formats. Whether an external WC will help improve your sound depends on on a few things, one of is your signal and monitoring ablity to hear any difference. You only can try it and see if it makes a difference or rather a big enough difference that your willing to pay for.

In general, a dedicated WC is meant for sending the exact same clk to multiple digital devices at the same time rather than using some sort of daisy chain clk method.

wordclock is g(o)od!!

the clock on the rme is pretty good.. so buy the wc-option and use it as master for the other devices...

and then when you get more things.... buy a wc generator.... i love the rosendahl btw

i had an rme clock until i tried the apogee big ben. it blew the rme out of the water